Constant Current Boost Controller for
Driving High Power LEDs
The MIC3230/1/2 are constant current boost switching
controllers specifically designed to power one or more
strings of high power LEDs. The MIC3230/1/2 have an
input voltage range from 6V to 45V and are ideal for a
variety of solid state lighting applications.
The MIC3230/1/2 utilizes an external power device which
offers a cost conscious solution for high power LED
applications. The powerful drive circuitry can deliver up to
70W to the LED system. Power consumption has been
minimized through the implementation of a 250mV
feedback voltage reference providing an accuracy of ±3%.
The MIC323x family is dimmable via a pulse width
modulated (PWM) input signal and also features an enable
pin for low power shutdown.
Multiple MIC3230 ICs can be synchronized to a common
operating frequency. The clocks of these synchronized
devices can be used together in order to help reduce noise
and errors in a system.
An external resistor sets the adjustable switching
frequency of the MIC3230/1. The switching frequency can
be between 100kHz and1MHz. Setting the switching
frequency provides the mechanism by which a design can
be optimized for efficiency (performance) and size of the
external components (cost). The MIC323x family of LED
drivers also offer the following protection features: Over
voltage protection (OVP), thermal shutdown and under-
voltage lock-out (UVLO).
The MIC3231 offers a dither feature to assist in the
reduction of EMI. This is particularly useful in sensitive EMI
applications, and provides for a reduction or emissions by
The MIC3232 is a 400kHz fixed frequency device offered
in a small 10-pin MSOP package. The MIC3230/1 are
offered in both the EPAD 16-pin TSSOP package and the
12-pin 3mm × 3mm MLF® package.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Bringing the Power to Light™
• 6V to 45V input supply range
• Capable of driving up to 70W
• Ultra low EMI via dithering on the MIC3231
• Programmable LED drive current
• Feedback voltage = 250mV ±3%
• Programmable switching frequency (MIC3230/1) or
400kHz fixed frequency operation (MIC3232)
• PWM Dimming and separate enable shutdown
• Frequency synchronization with other MIC3230s
• Protection features:
Over Voltage Protection (OVP)
Over temperature protection
Under-voltage Lock-out (UVLO)
• –40°C to +125°C junction temperature range
• Street lighting
• Solid state lighting
• General illumination
• Architectural lighting
• Constant current power supplies
Bringing the Power to Light is a trademark of Micrel, Inc.
MicroLeadFrame and MLF are registered trademarks of Amkor Technology.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com